The biomass macromolecular components (carbohydrates and
lignin) were determined on the basis of both NREL/TP-510-
42618 [27] and NREL/TP-510-42617 [28] analytical methods. In
these, acid-insoluble lignin is determined gravimetrically after acid
hydrolysis while acid-soluble lignin is quantified by ultraviolet
spectroscopy, respectively. The carbohydrates present in substrate
acid hydrolysates were determined by high performance liquid
chromatography (HPLC). Analyses were performed at 65 ◦C in an
Agilent Hi-Plex H column with a suitable guard column. Elution was
carried out with 5 mmol L−1 H2SO4 at a flow rate of 0.6 mL min−1.
Quantification was performed by external calibration of the component
sugars (cellobiose, glucose, xylose, and arabinose), acetic
acid and dehydration by-products (furfural and hydroxymethylfurfural).